This invention relates to a container coupling tool for coupling two shipping containers stacked one on the other.
In transporting many shipping containers by sea, they are stacked one on another, each container is coupled to the containers immediately above and below by container coupling tools, and the top containers are fixed to the ship deck by tightening fixing tools connecting the top containers to deck fixtures mounted to the ship deck by means of turnbuckles.
Such a container coupling tool is disclosed in examined Japanese utility model publication 5-23514. This coupling tool includes a tool body having top and bottom cones which can be turned to their respective engaged and disengaged positions by pivoting a handle supported on the tool body.
Two containers are coupled together by the container coupling tools in the following manner. With one container hung in the air, the top cones of coupling tools are inserted and engaged in holes formed at the four bottom corners of the container. With the coupling tools engaged in the holes in the bottom of the container, this container is placed on the other container to let the bottom cones slide into holes formed at the four top corners of the lower container. While the bottom cones are sliding into the holes, each bottom cone turns to its disengaged position by contact with the inner peripheral edge of the hole. When the bottom cone is completely inserted into the hole, it is turned back to the engaged position by a spring. The bottom cones thus engage in the holes of the lower container.
To unload the upper container, the bottom cone of each tool is disengaged from the container hole by pivoting the handle, and the upper container is raised with bottom cones disengaged from the holes of the lower container. When the upper container is lowered to a level at which the coupling tools are accessible to an operator, the operator pivots the handle of each tool to disengage the top cone from the container hole and remove the tool from the container.
With the conventional container coupling tool, the top and bottom cones are turned to their disengaged positions by pivoting the handle to the right or left, respectively. If an operator does not know which way to pivot the handle to disengage the bottom cone, he may pivot the handle in the wrong direction and disengage the top cone in an attempt to disengage the bottom cone.
For example, he may pivot the handles of the coupling tools all to the left, thus unknowingly disengaging the top cones, instead of the bottom cones. When the upper container is raised in this state, the coupling tools will be left on top of the lower container. To remove them, an operator has to climb onto the top of the lower container. This results in a waste of time and labor.
Containers are usually stacked in many tiers. Thus, some coupling tools are located at high levels. To disengage the bottom cones of such coupling tools, an operator on the deck has to pivot the handle of each tool to the left by using a special tool having a long rod. A skilled hand and a special tool are needed to pivot a handle at such a high level in a horizontal direction. Whether or not coupling tools are in engagement has to be judged by checking which way the handle is oriented. But it is extremely difficult to check the orientation of the handle from the deck.
A first object of this invention is to provide a container coupling tool which can minimize the possibility of wrong operation of the handle for disengaging the top and bottom cones.
A second object of this invention is to provide a container coupling tool which can be used is an upside down orientation.